DESCRIPTION OF THE PROBLEM
Manufacturing, testing and studying of semiconductors very often require that a wafer or sample of semiconductor material be transferred in a vacuum chamber from one operating position to another, for example, from an ion-implantation position to a surface-analyzing position. In spite of the fact that positioning of a sample in the vacuum chamber is typically done in polar coordinates (an angle and a radius vector), conventional standard manipulators used for this purpose, such as the model PM-600 of Huntington Mechanical Laboratories, Inc., Mountain View, Calif., have an orthogonal (X, Y) coordinate system with two slides moveable in mutually perpendicular directions. Thus an operator must transpose the polar coordinates to orthogonal coordinates in order to use conventional, standard manipulators; this is an inconvenient and time-consuming operation. For example, if semiconductor manufacturing specification calls for a wafer to be positioned at the polar coordinates of 150.degree. and 22 cm from a reference point and 0.degree. line, the operator must convert this, using trigonometric functions (sine and cosine), or mensuration with a protractor and ruler, to the orthogonal coordinates X=-19 cm. Y=11 cm, a time-consuming, and tedius operation which adversely affects any mass-production operation. Furthermore, the orthogonal manipulator is more complicated in construction and more expensive to manufacture, as it requires the use of two micrometers for positioning on two mutually-perpendicular axes.